1. Field of the Invention
The present invention relates to a method and an apparatus for cutting semiconductor ingots into sliced wafers by using wire saws.
2. Description of Prior Art
Conventionally, semiconductor wafers are obtained by cutting them out from semiconductor ingots one by one, by an Internal Diameter saw(I.D.Saw). However, in the above mentioned cutting operation performed by I.D.Saw warps on each cut-out surface are formed because of the resistance incurred between the cut-out surface and the I.D.Saw. And, the size of each warp on every wafer is quite different from the others, and the distribution of the warps is broad.
To solve the above defects, proposals such as those disclosed in unexamined Japanese Publication TOKU KAI HEI 1-1820011 and 5-16943 are offered, in which I.D.Saws are controlled by certain measures to enhance the flatness of the cut-out surfaces of the wafers.
However, for the purpose of performing the cutting operation by using the blades of an I.D.Saw in the above mentioned methods, a detection device for detecting the deflection of the internal peripheral cutter after each cut-out of wafers, and control means for controlling the deflection of the internal peripheral cutter during cutting operation are required. Therefore, the structure and the operation of the device become complicated and the cutting device becomes bulky.